1. Field of the Invention
The present invention relates to a multiple joint robot.
2. Description of the Related Art
A multiple joint robot for use in an industrial production line for producing food or medical products or the like must remain hygienic. In order to maintain the hygienic condition, the robot is regularly washed with water or cleaning agents. However, if components of the robot have rough surfaces, foreign objects or cleaning agent residues tend to be attached thereto. In order to prevent it, parts which move relative to each other may be formed into a labyrinth structure. For example, JP-A-63-123688 proposed an industrial robot in which a waterproof structure is provided between a swing table of a driven part and a holder of a fixed part.
A tip portion of an arm is the closest part of the robot to products, and thus it must be particularly kept hygienic. However, an end effector attached to the tip portion of the arm is subject to selection by a user, and thus a configuration thereof varies, depending on an intended application. Accordingly, it is difficult to provide a predetermined labyrinth structure between the tip portion of the arm and the end effector.
There is a need for a multiple joint robot which allows an end effector attachment of the robot to be kept hygienic.